The calculation method to convert a cost to an annual basis. The calculation converts a cost for a performance period that is less than one full year into an annual cost to correctly reflect the cost in a government cost estimate. This calculation is performed by first dividing the cost in the performance period by the number of days in the performance period to determine the corresponding daily cost and then multiplying the daily cost by 365.25 days to determine the annualized cost. To account for leap years, 365.25 is the average number of days in a year.